The ubiquity of mobile communication is for the benefit of emergency notifications. When an emergency session is initiated from an authenticated user equipment (UE), the UE determines whether its communication resources are sufficient to establish the emergency session. The UE is authenticated, e.g., using a Subscriber Identity Module (SIM, including a Universal SIM, a CDMA SIM or an International SIM) implemented in a SIM card such as a Universal Integrated Circuit Card (UICC). In case of insufficient resources due to other ongoing sessions, the UE terminates any ongoing communication and releases reserved bearer resources. In the packet-switched (PS) domain of mobile telecommunication, e.g., when the UE is wirelessly connected to an Internet Protocol (IP) Connectivity Access Network (IP-CAN) according to the 3rd Generation Partnership Project (3GPP), the UE registers an IP bearer at the IP-CAN.
UEs can be used in different countries requiring different emergency numbers. A traveller visiting a foreign country does not have to know the local emergency numbers. The UE or the SIM card can have a pre-programmed list of emergency numbers. For example, a network operator can issue a SIM card that includes a limited number of country-specific emergency numbers. When the UE recognizes that an emergency number is dialed, it initiates an emergency session setup that is routed by the network to an emergency entity, also when roaming abroad. Furthermore, the Global System for a Mobile communications network (GSM) includes functionality, e.g., the Over The Air technology, for updating and changing data in the SIM card without having to reissue it.
However, there are UEs without SIM functionality, e.g., if the SIM card is not inserted in the UE, or if the UE is not adapted to receive a SIM card such as tablets running a VoIP client with WiFi connectivity. Furthermore, also if the UE is authenticated based on its SIM data, setting up an emergency session may fail, e.g. if call routing fails, so that the UE will remain on the authenticated communication network.
As a consequence, even though there might be other networks that could assist the user with the emergency service, the UE will not automatically access those networks. A user would have to manually select another (e.g., unauthenticated) network, optionally after removing the SIM card from the UE, and trigger the emergency session setup by the UE. In an emergency situation, with the stress brought to the user by the situation, such tedious procedure is unrealistic and improper.
Factual serviceability reported for the year 2012 to the European Network and Information Security Agency (ENISA) for the electronic communications sectors indicate too frequent incidents of users that could not use their emergency service during the reported incidents, because a service outage of the emergency service occurred. The report is published under http://www.enisa.europa.eu/activities/Resilience-and-and-CIIP/Incidents-reporting/annual-reports/annual-incident-reports-2012. As a result, the user could not setup the emergency service, e.g. by dialing the emergency number 112.
More specifically, the emergency number 112 was unavailable in 37% of the incidents. The root cause identified for 75% of the reported incidents was “System failure”. Notably, this was the most frequent root cause category for each of the four services fixed and mobile telephony as well as fixed and mobile Internet. Within the category “System failure”, hardware failures were the most frequent cause, followed by software bugs. Network components most often affected by the “System failure” include switches in general (e.g., routers and local exchange points) and home location registers.